The present invention relates to a pump unit having two main axial displacement piston pumps and one or more auxiliary pumps connected with the pump unit. In particular, the present invention relates to a unique drive arrangement which simplifies the mounting of auxiliary pumps in such a pump unit.
It is a known practice to construct a pump unit in which two axial displacement piston pumps are mounted coaxially on a common drive shaft with a power input shaft perpendicular to the common drive shaft. The power input shaft and the common drive shaft are provided with bevel gears in meshing engagement to transmit power from the input shaft to the common drive shaft. This is illustrated the above-mentioned U.S. Patent Application, Ser. No. 845,908.
It is also known to modify such a pump unit to permit an auxiliary pump to be mounted as part of the same unit. This has required that the power input shaft be offset from the common drive shaft of the main pumps and that complicated gearing be used to connect the power input shaft with the common drive shaft. These gears are more difficult and expensive to manufacture than bevel gears.